Remote-controlled "zombie" networks operated by bottom-feeding spammers have become a serious problem that requires more industry action, the Federal Trade Commission is expected to announce on Tuesday.

The FTC and more than 30 of its counterparts abroad are planning to contact Internet service providers and urge them to pay more attention to what their customers are doing online. Among the requests: identifying customers with suspicious e-mailing patterns, quarantining those computers and offering help in cleaning the zombie code off the hapless PCs.

To be sure, computers infected by zombie programs and used to churn out spam are a real threat to the future of e-mail. One report by security firm Sophos found that compromised PCs are responsible for 40 percent of the world's spam--and that number seems to be heading up, not down.

But government pressure--even well-intentioned--on Internet providers to monitor their users raises some important questions. Will ISPs merely count the number of outbound e-mail messages, or actually peruse the content of e-mail correspondence? E-mail eavesdropping is limited by the Electronic Communications Privacy Act in the United States, but what about other countries without such laws? If these steps don't stop zombie-bots, will the government come back with formal requirements instead of mere suggestions the next time around?

The FTC said that its advice should not be alarming. "I think our recommendations are intended to provide flexibility by ISPs to implement them to the extent they can," Markus Heyder, an FTC legal adviser, said on Friday. "We have vetted them extensively with other partners and industry members."